This invention relates generally to the controlled release of vapors from a liquid source. It relates more particularly to the controlled release and dispersal of aromatic vapors for air fragrance and/or freshening by a system and method for controlled metering and release of such vapors from a liquid source to the surrounding atmosphere.
Room air fresheners typically function by absorbing or masking unpleasant odors. Manufacturers of such air freshener devices or products must predetermine the relationship needed between absorptive or masking capacity of a given fragrance material formulation, the desired useful life-span for the material, and mechanisms capable of delivering the desired fragrance or freshening effect to a surrounding space. In the class of air freshener devices whereby an aromatic formulation is allowed to vaporize into the air around it, thereby masking whatever other odors may be present, the useful life of the air freshening device is determined by the total volume of volatile material available, the vapor pressure of the volatile material, and the exposed surface area from which the volatile material can escape.
The prior art for the manufacture of such air freshener devices does not permit the use of aromatic formulations which have high vapor pressures, because these fluids evaporate relatively rapidly, thus producing an undesirably short usable life-span for the product. The use of stabilizers, fixatives and the like in such aromatic formulations can result in these additives accumulating at the surface intended for evaporation, thereby effectively blocking evaporation of the aromatic material to any useful degree and at the same time thwarting the intended use of any device using fluids containing such formulation. For this reason, fragrances containing such formulations having high vapor pressures are not typically used, and in general such formulations and those with high vapor pressures are avoided by the air freshener industry as unusable. Thus, the range of useful fragrance materials is thereby undesirably limited.
Also, various other prior art devices have been provided which are intended to control the release of vapors such as from deodorants, disinfectants or fragrances. For example, U.S. Pat. No. 2,412,326 to Dupuy discloses a vaporizing device in which the vaporization rate of material from a container is controlled by a cover having variable area openings. U.S. Pat. No. 2,111,025 to Galler discloses an unitary vapor generating device containing dual compartments which are each sealable by removable adhesive seals. Also, U.S. Pat. No. 2,572,329 to Foster discloses a room deodorizer including a container having a porous stopper element attached to a wick for controlling the rate of liquid evaporation from the container, the deodorizer being resealable by a screw top. U.S. Pat. No. 4,157,787 to Schwartz discloses an air freshener dispenser having a first layer of porous material covered by a second layer of non-porous material. Although these devices have been found useful, a need still exists for an improved vapor release system for the controlled release of vapors, particularly from more concentrated fragrance generating material sources having high vapor pressures.